Clot Chronicles: Menstruation, Contraception, Anticoagulation, & VTE — What Providers Should Know

Hello, my name is Bethany Samuelson Bannow. I am an Assistant Professor of Medicine in Hematology at Oregon Health and Science University. Today on Clot Chronicles, I will be discussing menstruation, anticoagulation, contraception, and VTE. 

Something that is super important to keep in mind that, unfortunately, we often forget is that a lot of patients with clots are also having menstrual bleeding. This is for a variety of reasons, not the least of which include that some of our treatments for menstrual bleeding actually increase the risk of clots in certain populations. My job today is to talk a little bit about how we can most safely manage anticoagulation in clot patients who are also menstruators. 

So, the first thing that is important to know and keep in mind is what is normal menstruation? Normal menstruation lasts about 2-7 days and it happens every 28 days, give or take a week or so. We know the median blood loss is about 53 mL, which should be a pretty small amount, but blood loss can actually become very high in the setting of anticoagulation, bleeding disorders, or other underlying issues. So, patients can become anemic, or iron deficient, or have other pretty significant barriers to their quality of life.

I always like to make sure that when I’m prescribing anticoagulation for a new clot, and when I’m following up on it, and then when I’m stopping anticoagulation, that I consider a few key things. First of all, when I’m starting anticoagulation in a patient who’s menstruating, I always ask about their menstrual history; do they have a history of heavy bleeding in the past, do they have a history of iron deficiency anemia, were they already on a contraceptive agent that perhaps contributed to this clot? Those are all things that we want to make sure we think about upfront. I always check a CBC and a ferritin at the time of starting anticoagulation to make sure that we’re not starting too in the hole, and then treat iron deficiency, of course.

The other thing that I always want to make sure that I talk about when starting anticoagulation is contraception. I think the knee-jerk reaction a lot of times is to pull away from any estrogen-containing agents because we’re worried they can cause a clot. Unfortunately, that also may be controlling the periods that we then may make worse with our anticoagulation. So, I actually allow my patients to stay on estrogen-containing contraception as long as they are on an anticoagulant. So don’t pull that away right away. 

It’s also super important that patients who are on anticoagulation have good contraception to prevent unplanned pregnancies, because, of course, that does also further increase the risk of clotting, and we really want to avoid pregnancies in the setting of warfarin and other teratogenic agents. So, those are things that I think about upfront. 

On follow-up visits, I always ask patients, “how are your periods; how long do they last, how long are you changing protection?” Anything more often than changing a pad or tampon every 1-2 hours qualifies as heavy menstrual bleeding, and there might need to be something done about that. So again, checking the CBC andferritin to make sure that we’re not developing iron deficiency anemia, but also talking about methods to control periods – and there are a plethora of options out there. 

My personal favorite is the levonorgestrel IUD—most commonly marketed as Mirena^®—which does a fantastic job of controlling periods, extremely efficacious contraception, and also does not increase the clot risk whatsoever. However, like I mentioned on anticoagulation, the estrogen-containing contraceptives are also options, as are a variety of progestin contraceptives, including the Nexplanon^®, etonogestrel implants, birth control pills, the patch, and ring. All of those are on the table as long as a patient is anticoagulated – but we want to make sure that we’re not causing our patients to hold their anticoagulation because their periods are so heavy and we’re not controlling them. 

So, that’s the thing that I do when I’m having follow-up visits, and then when I’m thinking about stopping anticoagulation there’s a few other things to keep in mind. In addition to all of the above issues, I want to make sure that a patient’s been off of the estrogen-containing contraceptives for at least 1 month before I stop anticoagulation, which typically means that we’ve had a Mirena placed, or some other progestin-only contraceptive made available to manage periods and to prevent pregnancy. 

We also want to do counseling about future pregnancies. Women who’ve had clots in the past are, of course, at an increased risk of clots in the future, particularly with pregnancy. So I want to make sure that a patient is well-educated on needing to let us know right away if she becomes pregnant, ideally coming to us for some preconception counseling or going to OB for preconception counseling so we can make sure that we talk about what a plan for anticoagulation would be during pregnancy. Then we want to make sure that there’s regular follow-up, again checking that CBC and ferritin to make sure that we’re avoiding iron deficiency anemia, which is one of the major complications of heavy menstrual bleeding and can really impact quality of life.

As long as we think of all those things throughout the course of anticoagulation, really we can make sure that our patients aren’t adversely affected from the anticoagulation from a uterine bleeding standpoint, or at least manage it if that does come up. 

So, thank you very much for your time today. If this is something that is of interest to you or your patients, you can follow myself and my colleague, Dr. Marybec Griffin, on @DrPeriodHackers on Twitter. We have a weekly tweetorial on managing heavy menstrual bleeding, consequences of menstrual bleeding, and lots of good education there. Thank you very much and have a great day.